Consider the following testcase
===============================
public class test
{
        /**
         *      Just to check whether all reasons for NullPointerException are documented.
         *      @throws NullPointerException for ReasonNo.1
         *      @throws NullPointerException for ReasonNo.2
         *      @throws ArithmeticException for ReasonNo.3
         *      @throws NullPointerException for ReasonNo.4
         */
        public void methodOne () throws NullPointerException, ArithmeticException
        {
        }
}


The Same Exception is documentd 3 times for various reasons, (one important being to increase readability of source files) and the Javadoc tool documents
only the first instance... 

Read below for the output by std.doclet,
=====================================================================
methodOne

public void methodOne()
               throws java.lang.NullPointerException,
                      java.lang.ArithmeticException

      Just to check whether all reasons for NullPointerException are documented. 

      Throws: 
            java.lang.NullPointerException - for ReasonNo.1 
            java.lang.ArithmeticException - for ReasonNo.3
==============================================================================

This behaviour is not documented, but highly desired.